What is the engine intake manifold?

In combustion engines, a mixture of air and fuel is ignited in the engine, giving the vehicle the necessary power required to drive. The engine intake manifold (or inlet manifold) a component made of aluminum or iron. It evenly delivers the air/fuel mixture to each of your engine’s cylinders, allowing for optimum combustion and engine power/efficiency. 

In some vehicles, the intake manifold also has conduit engine coolant following through it. 

The intake manifold is attached to the top of the engine by an intake manifold gasket. This seals the air/fuel mixture, preventing leaks from occurring.

Learn more about the intake manifold >


What causes intake manifold leaks?

A leaking intake manifold can affect the efficiency and performance of your engine. The intake manifold gasket is usually the main cause of leaks. This is due to the high levels of heat and pressure that the component is regularly put under. 

Sometime the intake manifold itself can crack, causing an intake air leak.

Another very common intake manifold issue is to do with all of the emission control and vacuum hoses that can come off or crack causing intake manifold air leaks.

If there is a leaking intake manifold gasket, cracked manifold, or any other vacuum leaks from disconnected or cracked vacuum hoses then you may have a higher engine rpm at idle, a lean air / fuel ratio, poor engine performance and increased greenhouse gas exhaust emissions.


Symptoms of intake manifold gasket leaks:

Common symptoms of leaks and/or damage include:

Reduced engine performance – An intake manifold leak will actually cause more air to enter your engine. This is because the air pressure inside the manifold is lower than the surrounding air. A leak will suck in extra air, affecting the air/fuel ratio and resulting in less efficient engine combustion (lean mixture). This will reduce the power and performance of your engine.

Decreased fuel consumption – Any changes to your engine’s optimum air/fuel ratio will result in your vehicle using fuel less effectively. This is because the fuel is unable to burn properly. 

Engine light on – The engine light may turn on if your car’s Manifold Absolute Pressure (MAP)  or Mass Air Flow (MAF) sensors detect too much air entering your engine combustion chamber. 

Higher engine idle RPM – the excess air entering the engine from the intake manifold leak can cause the engine to rev faster and possibly surge at idle.

Engine surge at slight throttle – an inlet air leak can also contribute to your car surging at light throttle and low load conditions.

Engine light diagnostics >

Coolant leaks and overheating – If your engine has a coolant heated intake manifold, then it may develop a coolant leak, 

This can result in the engine overheating, which can cause serious, expensive damage. If coolant leaks are appearing under your vehicle and the temperature gauge is higher than normal, we recommend that you get your car seen by a mechanic as soon as possible.


Engine intake manifold leak inspection in Hamilton

Is your vehicle’s intake manifold in need of an inspection? At Grimmer Motors, our team of skilled mechanics can quickly identify and fix water / coolant and air leaks.

We can run diagnostic tests on your vehicle, which allow us to determine if there is an intake manifold air leak, with too much air in your engine. We can then thoroughly examine the source of the leak, replacing parts as needed and preventing it from causing more damage.

For all intake manifold, intake manifold gasket, and intake manifold vacuum hose replacements in Hamilton, contact Grimmer Motors today!

Please Note – we don’t generally stock or supply just “parts only” for this service. We are a general automotive repair workshop. If you are able to bring your vehicle to us, we can diagnose the problem, find and fit the necessary parts, or organise the appropriate service for you.


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